Video playback sync question

Hello fellow forum members.
I recently had to work on a Scoring Competition and had some issues with the sync of the video.

Video here

Let me explain:
I have imported the video and extracted the audio from the video file (only dialogs). After hitting play in Cubase, the video was out of sync, without plugins without nothing.
I converted the video file to ProRes and had the same results. I have to say that ONLY playback is affected. When i tested to find a frame, on a scene change and exported the audio it was perfect in sync. So the conclusion is ONLY what you see is wrong when you hit play.
After reading some posts in the Nuendo forum i found out that i have to use video offset in the Studio setup. So i did and it worked perfect.
I was working on 25fps and found out that i was 5-6 frames off sync. After calculating how many ms is 1 frame at 25fps the result was 1frame=40ms. So i did set the offset to 200 (5frames) and i could work. But if someone wants to be perfect in time, how could i say if 6frames(240ms) is more accurate?
The real question is:
Is there any way to calculate the exact offset not only by visual testing?
I am on Cubase 10.0.60 and Win7.
Thank you in advance for any reply!